Method and system for guard band detection and frequency offset detection

ABSTRACT

Methods and systems are provided for guard band detection and frequency offset detection. For each of a plurality of downconverted signals, frequency related information associated with one or more corresponding circuits used in obtaining the plurality of downconverted signals may be determined; and based on the determined frequency related information, one or both of a band stacking operation and a channel stacking operation may be performed. During the band stacking operation, frequency bands are not stacked on each other or stacked frequency bands do not overlap. During the channel stacking operation, channels are not stacked on each other or stacked channels do not overlap. The frequency related information may be determined based on predefined frequency related parameters associated with the corresponding circuits. Frequency corrections may be performed, on output signals corresponding to the band stacking operation and/or the channel stacking operation, based on the frequency related information.

CLAIM OF PRIORITY AND CROSS-REFERENCE TO RELATEDAPPLICATIONS/INCORPORATION BY REFERENCE

This patent application is a continuation of U.S. patent applicationSer. No. 14/711,057, filed on May 13, 2015, which is a continuation ofU.S. patent application Ser. No. 13/917,794, filed on Jun. 14, 2013,which in turn makes reference to, claims priority to, and claims benefitfrom U.S. Provisional Application Ser. No. 61/660,122, filed on Jun. 15,2012. Each of the above stated applications is hereby incorporatedherein by reference in its entirety.

This patent application also makes reference to:

-   U.S. patent application Ser. No. 13/762,939 filed on Feb. 8, 2013;    and-   U.S. patent application Ser. No. 13/783,130 filed on Mar. 1, 2013.

Each of the above stated applications is hereby incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to communication systems.More specifically, certain embodiments of the invention relate to amethod and system for guard band detection and frequency offsetdetection.

BACKGROUND OF THE INVENTION

In satellite reception applications, dielectric resonant oscillators(DROs) are utilized in low noise block downconverters (LNBs) to generateclock signals. However, dielectric resonant oscillators (DROs) maybecome very unstable (e.g., due to temperature) and may cause frequencyerrors of the order of approximately 5 MHz.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with the present invention as set forth inthe remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method for guard band detection and frequency offsetdetection, substantially as shown in and/or described in connection withat least one of the figures, as set forth more completely in the claims.

Various advantages, aspects and novel features of the present invention,as well as details of an illustrated embodiment thereof, will be morefully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary network comprisingsatellite television components, in accordance with an exampleembodiment of the invention.

FIG. 2 is a block diagram illustrating an exemplary signal processingcircuit within a satellite reception assembly, in accordance with anexample embodiment of the invention.

FIG. 3 is a block diagram illustrating an exemplary stacking scheme, inaccordance with an example embodiment of the invention.

FIG. 4 is a block diagram illustrating an exemplary circuit that isoperable to provide guard band detection and frequency offset detection,in accordance with an example embodiment of the invention.

FIG. 5 is a block diagram illustrating an exemplary circuit that isoperable to provide guard band detection and frequency offset detection,in accordance with an example embodiment of the invention.

FIG. 6 is a block diagram illustrating an exemplary implementation offrequency analysis, in accordance with an example embodiment of theinvention.

FIG. 7 is a flow chart illustrating exemplary steps for guard banddetection and frequency offset detection, in accordance with an exampleembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As utilized herein the terms “circuit” and “circuitry” refer to physicalelectronic components (i.e. hardware) and any software and/or firmware(“code”) which may configure the hardware, be executed by the hardware,and/or otherwise be associated with the hardware. As utilized herein,“and/or” means any one or more of the items in the list joined by“and/or”. As an example, “x and/or y” means any element of thethree-element set {(x), (y), (x, y)}. As another example, “x, y, and/orz” means any element of the seven-element set {(x), (y), (z), (x, y),(x, z), (y, z), (x, y, z)}. As utilized herein, the term “exemplary”means serving as a non-limiting example, instance, or illustration. Asutilized herein, the terms “e.g.,” and “for example” set off lists ofone or more non-limiting examples, instances, or illustrations. Asutilized herein, a device/module/circuitry/etc. is “operable” to performa function whenever the device/module/circuitry/etc. comprises thenecessary hardware and code (if any is necessary) to perform thefunction, regardless of whether performance of the function is disabled,or not enabled, by some user-configurable setting.

Certain embodiments of the invention can be found in a method and systemfor guard band detection and frequency offset detection. In variousembodiments of the invention, a signal processing circuit, which isoperational within a satellite reception assembly, may be operable toanalyze actual frequency information corresponding to a plurality ofdownconverted signals. Each of the plurality of downconverted signalsmay be downconverted using one or more corresponding local oscillators(LOs) in the signal processing circuit. For each of the downconvertedsignals and based on the analyzing, one or more of at least thefollowing may be determined by the signal processing circuit: (1) one ormore frequency offsets, which are associated with the one or morecorresponding local oscillators (LOs), in relation to correspondingstandard LO frequencies, and (2) one or more actual guard bands betweenadjacent frequency bands. The signal processing circuit may be operableto generate, for the plurality of downconverted signals, information onone or more of at least the following: the determined frequency offsetsand the determined actual guard bands.

The signal processing circuit may then be operable to perform, based onthe generated information and using, for example, a band/channelstacking module in the signal processing circuit, one or both of a bandstacking operation and a channel stacking operation so that: (1) duringthe band stacking operation, frequency bands are not stacked on eachother or stacked frequency bands do not overlap, and (2) during thechannel stacking operation, channels are not stacked on each other orstacked channels do not overlap during the channel stacking operation.The signal processing circuit may also be operable to perform, based onthe generated information and using the band/channel stacking module,frequency corrections, in compliance with standard band frequencies andstandard channel frequencies, on output signals of the band stackingoperation or output signals of the channel stacking operation, forchannel tuning in a gateway. In this regard, the signal processingcircuit may be operable to downconvert a plurality of radio frequency(RF) signals to the plurality of downconverted signals correspondingly,where each of the RF signals may correspond to one or more satellitefrequency bands, and the downconverted signals may comprises, forexample, L-band signals or baseband signals. The signal processingcircuit may be operable to perform the analyzing, the determining andthe generating, using, for example, a frequency detection module in thesignal processing circuit.

In an exemplary embodiment of the disclosure, the frequency detectionmodule may comprise a demodulator. In other instances, the frequencydetection module may comprise, for example, at least a portion of ademodulator, where the at least a portion of the demodulator maycomprise a phase locked loop (PLL).

In an exemplary embodiment of the disclosure, the plurality ofdownconverted signals may be in digital domain and the frequencydetection module may be operational in the digital domain. In suchinstances, the frequency detection module may perform the analyzingusing one or more of the following: a fast fourier transform (FFT), anedge detection and a center-of-mass computation. The frequency detectionmodule may also determine, based on the edge detection, a symbol rateassociated with each channel for channel filtering in the band/channelstacking module, during at least the channel stacking operation, forexample.

In an exemplary embodiment of the disclosure, each of the localoscillators (LOs) may comprise a dielectric resonant oscillator (DRO).The generated information may comprise, for example, a form of a matrix,where each element of the matrix may correspond to one of at least thefollowing: a particular frequency offset associated with a particularlocal oscillator (LO) and a particular actual guard band associated witha particular downconverted signal.

FIG. 1 is a block diagram illustrating an exemplary network comprisingsatellite television components, in accordance with an exampleembodiment of the invention. Referring to FIG. 1, there is shown anin-premises network 100, a satellite reception assembly 106, a pluralityof satellites 130, and a network link 108 for connecting the satellitereception assembly 106 and the in-premises network 100.

The in-premises network 100 may be setup and/or configured to serviceparticular premises 101 (e.g., residential or commercial). In thisregard, the in-premises network 100 may facilitate providing broadbandand/or television (or other similar content broadcast) access in thepremises 101. The in-premises network 100 may comprise, for example, agateway 102 and a plurality of client devices, of which televisions 104₁-104 ₃ are shown.

The plurality of satellites 130 may be utilized to transmit (beam down)satellite signals 140. In this regard, the satellite signals 140 may beutilized to broadcast satellite television content. The satellitesignals 140 may comprise, for example, K, Ka, and/or Ku band DirectBroadcast Satellite (DBS) signals. The disclosure, however, is notlimited to any particular type of satellite signals.

The satellite reception assembly 106 may be referred to as a satellite“dish”. In this regard, the satellite reception assembly 106 maycomprise circuitry operable to receive satellite signals (e.g., thesatellite signals 140), and to process the received satellite signals,such as to recover data carried in the satellite signals (e.g.,television channels, media content, etc.), and configure a suitableoutput corresponding to the recovered data for transmission to otherdevices that may handle use and/or distribution of the data (e.g., tothe gateway 102 via the communication link 108). The satellite receptionassembly 106 may comprise a signal processing circuit 120. In thisregard, the signal processing circuit 120 may be, for example, part ofthe satellite reception assembly 106 (e.g., it may be mounted on a boomat or near the focal point of a parabolic reflector), and may comprisecircuitry for capturing and processing satellite signals 140.

The signal processing circuit 120 may utilize a plurality of localoscillators (LOs) for processing the satellite signals 140. The localoscillators (LOs) may comprise, for example, dielectric resonantoscillators (DROs). Over time, due to temperature or other environmentalconditions, these DROs may become unstable and their frequencies maydrift and may result in frequency and timing errors that may be of theorder of approximately 5 MHz. In some instances where the bandwidthwhich may be handled by the gateway 102 may be wide enough to handlethis variation in frequency, this may not be an issue. However, ininstances of band stacking or channel stacking performed in the signalprocessing circuit 120, this frequency error may become an issue sinceoverlapping of stacked channels may result.

The communication link 108 may comprise one or more wired, wireless,and/or optical links. The communication link 108 may comprise, forexample, a wired (e.g., coaxial and/or twisted-pair) and/or wirelesscommunication medium which carries physical layer symbols in accordancewith, for example, Multimedia over Coax Alliance (MoCA), Ethernet,and/or DBS standards. In some instances, the gateway 102 may beconfigured to terminate other communication links (not shown), which maycomprise, for example, a coaxial or twisted-pair cable and/or an opticalfiber which carries physical layer symbols in accordance with, forexample, DSL, DOCSIS, or Ethernet standards (e.g., to facilitate cabletelevision, terrestrial television, and/or Internet accessibility).

The gateway 102 may comprise circuitry operable to receive the signalscommunicated over a plurality of links (e.g., the link 108), process thesignals as necessary for outputting information contained therein via aplurality of internal links 103 (e.g., 103 ₁-103 ₃) within thein-premises network 100. In this regard, the plurality of internal links103 may comprise wired, wireless, and/or optical links that may besuited for use in an environment such as the in-premises network 100.For example, the internal links 103 may comprise wired connections(e.g., HDMI connections, Display Port links, MoCA links, or Ethernetconnection), and/or wireless connections (e.g., Wi-Fi, ZigBee, wirelessUSB, or the like). The gateway 102 may also comprise circuitry operableto transmit signals via the link 108 and/or any other external links(i.e., links connecting the gateway 102 to external entities, such asbroadcast or service head-ends). Accordingly, the term “gateway” in thisdisclosure refers to a client device which may perform satellite set-topbox (STB) functions, cable television receiver functions, terrestrialtelevision receiver functions, WAN/LAN modem functions, etc. In thisregard, “satellite set-top box” functions may comprise functionsnecessary for delivering data from the satellite reception assembly 106to devices within the premises 101.

The gateway 102 may be configured to service a plurality of clientdevices, which may comprise devices that may communicate with thegateway 102 via one or more point-to-point media links (e.g., HDMI,Display Port, analog video links, analog video links, or the like). Anexample of such client devices is televisions (e.g., televisions 104₁-104 ₃) and similar devices that may be used in displaying or playingback multimedia content that may be broadcasted (e.g., via terrestrialsignals, satellite signal, cable signal, and/or over the Internet).

In operation, the in-premises network 100 may be setup and/or used toprovide various services (e.g., broadband and/or television access)within the premises 101. For example, the in-premises network 100 maycomprise an Internet Protocol (IP) based network that interconnectsvarious devices, the gateway 102 and the client devices (e.g., thetelevisions 104 ₁-104 ₃), within a physical space (e.g., the premises101) to each other and/or to access networks for various IP-basedservices such as IP-based TV (IPTV) services. In this regard, IPTVservice may be applications in multicast networks that may providedelivery of broadcast TV and other media-rich services over secure,end-to-end operator managed broadband IP data networks. The gateway 102may be utilized to service the in-premises network 100, such as byproviding broadband and/or television (or other media content) access toa plurality of client devices (e.g., the televisions 104 ₁-104 ₃) withinthe in-premises network 100. In this regard, the gateway 102 may receivesignals carrying content that may be forwarded to the client devices foruse thereby. For example, the content used (e.g., displayed/played) bythe televisions 104 ₁-104 ₃ may be based on satellite televisionbroadcasts. In this regard, the satellite reception assembly 106 may beconfigured to receive the satellite signals 140, and to process thesignals such that the signal (or corresponding signals) may be fed intothe gateway 102 (via the link 108) for use within the in-premisesnetwork 100 (e.g., being forwarded to the televisions 104 ₁-104 ₃ viacorresponding local links 103 ₁-103 ₃). In some instances—e.g., when thetelevisions 104 ₁-104 ₃ may correspond to a plurality of televisionsused in different locations (e.g., rooms) in a single dwelling ordifferent units (e.g., apartments) in multi-unit building—it may bedesirable to use the televisions 104 ₁-104 ₃ for concurrently viewingdifferent contents.

The satellite reception assembly 106 may be configured to concurrentlyreceive a plurality of satellite signal beams (i.e., belonging todifferent broadcasts). In this regard, the plurality of satellite signalbeams may comprise signals transmitted by different satellites and/orsignals transmitted by the same satellite with different polarization.Similarly, the gateway 102 may be configured to concurrently handlemultiple feeds, which may correspond to different users. In variousexample implementations, accommodating concurrent servicing (viewing)based on different satellite feeds may be achieved by use of channelstacking and/or band stacking technologies that may be utilized toincrease the number of viewing places in the premises 101, whilesimultaneously minimizing installation and service costs. For example,in the signal processing circuit 120 within the satellite receptionassembly 106, channel stacking may be implemented by taking multiplechannels from different frequency bands and stacking or combining themtogether for transmission over the same physical medium (e.g., the link108). Similarly, band stacking may be implemented by taking a pluralityof frequency bands (or sub-bands) and stacking or combining themtogether for transmission.

In an exemplary embodiment of the disclosure, the signal processingcircuit 120 may be operable to perform one or more of at least thefollowing: guard band detection and frequency offset detection so thatwhen stacking is done, one channel or band is not stacked, placed on topof another channel or band, or overlap with another channel or band.

FIG. 2 is a block diagram illustrating an exemplary signal processingcircuit within a satellite reception assembly, in accordance with anexample embodiment of the invention. Referring to FIG. 2, there is shownthe signal processing circuit 120. The signal processing circuit 120 maybe as described with respect to FIG. 1, for example. The signalprocessing circuit 120 may comprise, for example, a plurality of lownoise block downconverters (LNBs) 202 ₁-202 _(N), a combiner 204, afrequency detection module 230 and a link driver 206.

Each of the LNBs 202 ₁-202 _(N) may comprise circuitry operable toreceive and handle RF satellite signals (e.g., the satellite signals140), which may be captured via a reflector of a satellite receptionassembly (e.g., the satellite reception assembly 106). In this regard,each LNB 202 _(i) may be configured to perform, at least, such functionsas low-noise amplification, filtering, and downconverting on aparticular received RF (satellite) signals, to enable generatingcorresponding intermediate frequency (IF) or even baseband signals suchas the downconverted signals 205. In this regard, the IF signals 205 maybe, for example, in the L-band (950-2150 MHz), half-L-band (950-1450MHz), extended-L-band (250-2150 MHz, 300-2350 MHz), and the like. Thedisclosure, however, is not so limited, and the IF signals 205 may spanany suitable frequency range. Having N (where N is an integer number)LNBs in the signal processing circuit 120, as illustrated in FIG. 2, mayallow receiving N satellite (RF) signals, labeled RF₁ to RF_(N). In thisregard, each RF; signal may correspond to a unique/distinct satellitesignal and correspond to one or more satellite frequency bands, with thesignals differing, for example, based on the source or the polarization(e.g., RF₁ may correspond to a first polarization of a first satellite,RF₂ may correspond to second polarization of the first satellite, RF₃may correspond to a first polarization of a second satellite, and soon). Each of the LNBs 202 ₁-202 _(N) may comprise one or more localoscillators (LOs) such as LO₁-LO_(N). These LOs may be used, forexample, to downconvert RF signals (RF₁-RF_(N)) to correspondingdownconverted signals 205.

The frequency detection module 230 may comprise circuitry operable toreceive downconverted signals 205. The frequency detection module 230may be operable to perform analysis of actual frequency informationcorresponding to the downconverted signals 205 and generate information(or data) 210 based on the analysis. For example, the information 210may comprise at least the following: frequency offsets (in relation tocorresponding standard LO frequencies) associated with LO₁-LO_(N) andactual guard bands between adjacent frequency bands. In some instances,the information 210 may also comprise symbol rate information associatedwith the downconverted signals 205. The generated information 210 may becommunicated to the combiner 204, for example, for being used by aband/channel stacking module 220 in the combiner 204.

The combiner 204 may be configured to process and combine input signalscorresponding to the received RF signals (RF₁ to RF_(N))—i.e., outputsof the LNBs 202 ₁-202 _(N). For example, the combiner 204 may beoperable to amplify, downconvert, filter and/or digitize at least aportion of the input signals received from the LNBs 202 ₁-202 _(N). Forexample, the combiner 204 may comprise a band/channel stacking module220 which may be operable to perform a band stacking operation and/or achannel stacking operation. The combiner 204 may be configured tosupport full-spectrum (or full band)—i.e., to capture an entire spectrum(or an entire band) of each of one or more signals of interest which maybe concurrently digitized, or to only digitize a portion of the inputsignals, such as depending on which channels (or sub-bands) in thesignals are selected by client devices (e.g., which television channelsare being consumed by the client devices). Once the processing of theinput signals (or portions thereof) is complete, the combiner 204 may beoperable to recover information carried in the signals (e.g., one ormore channels contained therein), and may generate output signals (e.g.,M output signals, where M is an integer number) carrying the recoveredinformation. The output signals may be sent to the link driver 208, fortransmission thereby (e.g., to the gateway 102). In some instances, theoutput signals may be further processed in the combiner 204 before beingforwarded to the link driver 208. For example, the combiner 204 may beoperable to convert to analog, upconvert, filter, and/or amplify theoutput signals.

The link driver 206 may be operable to process signals generated via thecombiner 204 (e.g., comprising recovered information) and generatesignals that may be transmitted onto a link to a corresponding link-peerdevice, such as a gateway/STB (e.g., link 108 to gateway 102 of FIG. 1)in a format supported by the link-peer device. For example, the linkdriver 206 may be operable to packetize and transmit data received viasignals RF₁-RF_(N), in accordance with one or more networking standards(e.g., Ethernet, Multimedia over Coax Alliance (MoCA), DOCSIS, and thelike) to a link-peer device that receives satellite data using suchstandards. Additionally, or alternatively, the link driver 206 may beoperable to perform operations (e.g., digital to analog conversion,modulation, frequency conversion, etc.) for outputting the dataaccording to one or more multimedia standards (e.g., ATSC, DVB-S,ISDB-S, and the like) to enable receiving satellite data by clientdevices using such standards. The output of the link driver 206 maycomprise, for example, a plurality of IF signals, in a particular rangeto which the link-peer device (e.g., the gateway 102) may tune. Forexample, each of the IF signals may be in the L-band (950 MHz to 2150MHz).

In various example implementations, the band/channel stacking module 220may be configured to handle and/or support channel stacking and/or bandstacking using, for example, integrated stacking based architectures. Inthis regard, integrated stacking based architectures may comprise, forexample, analog stacking architectures or digital stackingarchitectures. For example, in an example implementation, an analogstacking circuit may be used, and may comprise integrated filters forexample. The filters may be configured to filter through particularportions (e.g., corresponding to particular channels or sub-bands). Theanalog stacking circuit may provide analog capture utilizing an analogmultiple input and multiple output crossbar (Xbar). In this regard, thecrossbar (Xbar) may be configured such that one or more inputs(comprising particular channels or sub-bands) may be combined and mappedto one or more outputs. In another example implementation, a digitalstacking circuit may be used, to provide digital capture using full bandstacking. The digital stacking circuit may be operable to providedigital capture utilizing a digital multiple input and multiple outputdigital crossbar. Furthermore, to allow for the digitization, thedigital stacking circuit may be configured to provide analog-to-digitalconversion (and, if needed, digital-to-analog conversion, such as whenthe system output need be analog).

In operation, the frequency detection module 230 may be operable toanalyze actual frequency information corresponding to a plurality ofdownconverted signals 205. Each of the plurality of downconvertedsignals 250 may be downconverted using one or more corresponding localoscillators (e.g., the LO₁ in the LNB 202 ₁). For each of thedownconverted signals 205 and based on the analyzing, one or more of atleast the following may be determined by the frequency detection module230: (1) one or more frequency offsets, which are associated with theone or more corresponding local oscillators (e.g., LO₁), in relation tocorresponding standard LO frequencies, and (2) one or more actual guardbands between adjacent frequency bands. The frequency detection module230 may be operable to generate, for the plurality of downconvertedsignals 205, information 210 on one or more of at least the following:the determined frequency offsets and the determined actual guard bands.The generated information 210 may be communicated to the band/channelstacking module 220.

The band/channel stacking module 220 may then be operable to perform,based on the communicated generated information 210, one or both of aband stacking operation and a channel stacking operation so that: (1)during the band stacking operation, frequency bands are not stacked oneach other or stacked frequency bands do not overlap, and (2) during thechannel stacking operation, channels are not stacked on each other orstacked channels do not overlap during the channel stacking operation.The band/channel stacking module 220 may also be operable to perform,based on the communicated generated information 210, frequencycorrections, in compliance with standard band frequencies and standardchannel frequencies, on output signals of the band stacking operation oroutput signals of the channel stacking operation, for channel tuning ina gateway such as the gateway 102 of FIG. 1.

In an exemplary embodiment of the disclosure, the generated information210 may comprise, for example, a form of a matrix 212, where eachelement of the matrix 212 corresponds to one of at least the following:a particular frequency offset associated with a particular localoscillator (e.g., one of the LO₁-LO_(N)) and a particular actual guardband associated with a particular downconverted signal (e.g., one of thedownconverted signals 205).

FIG. 3 is a block diagram illustrating an exemplary stacking scheme, inaccordance with an example embodiment of the invention. Referring toFIG. 3, there is shown a scheme 300 for staking channels or bands fromdifferent satellite beams. In this regard, use of the scheme 300 mayallow combining content from multiple satellite signals such as thesatellite signals 140 of FIG. 1 onto a single physical link forconveyance to a gateway/set-top box (STB), such as the gateway 102 ofFIG. 1, for example.

In the example implementation shown in FIG. 3, channels (or bands) fromtwo satellite (RF) signals 310 and 320 may be downconverted and then bestacked onto a single IF signal. The satellite signal 310 may comprise,for example, portions 311, 312, 313 and guard bands 313, 314. Thesatellite signal 320 may comprise, for example, portions 322, 323 and aguard band 324. The portions 311, 312, 313, and the portions 322, 323may correspond to, for example, individual channels or sub-bands in thesatellite signals 310 and 320 respectively. In this regard, initially,each of the received satellite signals 310 and 320 may be downconvertedvia corresponding LNBs such as the LNBs 202 ₁ and 202 ₂. Due tofrequency offsets 336, 346 associated with the LO₁ used in the LNB 202 ₁and the LO₂ used in the LNB 202 ₂ respectively, the actual downconverted(IF) signals 330, 340 may be different from corresponding standarddownconverted (IF) signals (without frequency drifts). In this regard,the signal 330 may comprise actual guard bands 334, 335 which may bedifferent from corresponding standard guard bands (without frequencydrifts), for example. The signal 340 may comprise actual guard band 344which may be different from corresponding standard guard band (withoutfrequency drifts), for example.

The signals 330, 340 may then be input to a band/channel stacking modulesuch as, for example, the band/channel stacking module 220. In thisregard, the band/channel stacking module 220 may be configured tocombine the content (e.g., the portions 311, 312, 313, 322, 323) of thesignals 330, 340, such as by stacking channels or bands within thesesignals 330, 340 onto a single signal 350. During the band stackingoperation or the channel stacking operation, the band/channel stackingmodule 220 may utilize information on the frequency offsets 336, 346 andthe actual guard bands 334, 335, 344 for the band stacking or thechannel stacking so that frequency bands (sub-bands) or channels in thesignal 350 are not stacked on each other, or stacked frequency bands(sub-bands) or stacked channels do not overlap. The band/channelstacking module 220 may then be operable to perform frequencycorrection, in compliance with standard band frequencies and standardchannel frequencies, on the signal 350 so as to generate a signal 360.In this regard, the signal 360 may comprise a frequency band withinstandard tuning range for channel tuning by a gateway such as thegateway 102.

Accordingly, since the gateway 102 is operable to tune to a frequencyband of the signal 360, the gateway 102 may be enabled to concurrentlyreceive satellite content carried in the portions 311, 312, 313 of thesatellite signal 310 and in portions 322, 323 of the satellite signal320. The satellite signals 310, 320 may comprise, for example, signalsfrom satellite transponders transmitting content (e.g., televisionchannels) that have been selected for consumption by the gateway 102.

FIG. 4 is a block diagram illustrating an exemplary circuit that isoperable to provide guard band detection and frequency offset detection,in accordance with an example embodiment of the invention. Referring toFIG. 4, there is shown a system 400. The system 400 may comprisesuitable circuitry, logic, code, and/or interfaces for performing and/orsupporting one or both of band stacking and channel stacking. Input RFsignals RF₁-RF_(N) (N is an integer number) may correspond to differentsatellite signals (i.e., originating from different sources and/orhaving different polarization). The system 400 may comprise a relevantportion of the signal processing circuit 120. For example, the system400 may correspond to the LNBs 202 ₁-202 _(N), the frequency detectionmodule 230 and at least a portion of the combiner 204 including theback/channel stacking module 220, described with respect to FIG. 2. Inthis regard, the system 400 may comprise, for example, a plurality oflow-noise amplifiers (LNAs) 402 ₁-402 _(N), a plurality of mixers 404₁-404 _(N), a plurality of filters 406 ₁-406 _(N), a plurality ofanalog-to-digital converters (ADCs) 408 ₁-408 _(N), a frequencydetection module 430, and a band/channel stacking module 420. The mixers404 ₁-404 _(N) may receive input signals from LO₁-LO_(N) respectively.

The frequency detection module 430 may be substantially similar to thefrequency detection module 230 described with respect to FIG. 2, forexample. The band/channel stacking module 420 may be substantiallysimilar to the band/channel stacking module 220 described with respectto FIG. 2, for example. Each of the LNA 402 ₁-402 _(N) may be operableto amplify, for example, weak satellite signals (e.g., RF₁-RF_(N)). Eachof the mixers 404 ₁-404 _(N) may be operable to downconvert a satellitefrequency band to, for example, an IF band or even to a basebandutilizing the LO₁-LO_(N) respectively. For example, one or more X, Kuand/or Ka satellite frequency bands may be downconverted to L-band. Eachof the downconverted signals 405 ₁-405 _(N) may be input to thefrequency detection module 430. Frequency information associated witheach of the signals 405 ₁-405 _(N) may then be analyzed by the frequencydetection module 430. The frequency detection module 430 may be operableto generate, based on the analyzing, information 410 which may beinputted to the band/channel stacking module 420. In this regard, theinformation 410 may be substantially similar to the information 210described with respect to FIG. 2, for example. The filters 406 ₁-406_(N) may be operable to filter signals 405 ₁-405 _(N), based on one ormore criteria. For example, the filters 406 ₁-406 _(N) may be configuredas low-pass filters (LPFs)—that is to pass low-frequency signals (belowparticular threshold, or a “cutoff frequency”) and to attenuate signalswith frequencies higher than the “cutoff frequency”. The ADCs 408 ₁-408_(N) may be operable to perform analog-to-digital conversions (e.g., onoutputs of the filters 406 ₁-406 _(N)).

In an exemplary operation, the frequency detection module 430 mayperform functions as described with respect to the frequency detectionmodule 230 of FIG. 2, for example. In an exemplary embodiment of thedisclosure, the frequency detection module 430 may comprise ademodulator 440. For example, in some implementation where there is aplurality of demodulators in the signal processing circuit 120, anyunused demodulator may be utilized by the signal processing circuit 120as the frequency detection module 430. In other instances, the frequencydetection module 430 may comprise at least a portion of the demodulator440, and the at least a portion of the demodulator 440 may comprise, forexample, a phase locked loop (PLL) 442. In this regard, for example, theportion of the demodulator 440 for the frequency detection module 430may be implemented without a forward error correction (FEC).

FIG. 5 is a block diagram illustrating an exemplary circuit that isoperable to provide guard band detection and frequency offset detection,in accordance with an example embodiment of the invention. Referring toFIG. 5, there is shown a system 500. The system 500 may comprisesuitable circuitry, logic, code, and/or interfaces for performing and/orsupporting one or both of band stacking and channel stacking. Input RFsignals RF₁-RF_(N) (N is an integer number) may correspond to differentsatellite signals (i.e., originating from different sources and/orhaving different polarization). The system 500 may comprise a relevantportion of the signal processing circuit 120. For example, the system500 may correspond to the LNBs 202 ₁-202 _(N), the frequency detectionmodule 230 and at least a portion of the combiner 204 including theback/channel stacking module 220, described with respect to FIG. 2. Inthis regard, the system 500 may comprise, for example, a plurality oflow-noise amplifiers (LNAs) 502 ₁-502 _(N), a plurality of mixers 504₁-504 _(N), a plurality of filters 506 ₁-506 _(N), a plurality ofanalog-to-digital converters (ADCs) 508 ₁-508 _(N), a frequencydetection module 530, and a band/channel stacking module 520. The mixers504 ₁-504 _(N) may receive input signals from LO₁-LO_(N) respectively.

The frequency detection module 530 may be substantially similar to thefrequency detection module 230 described with respect to FIG. 2, forexample. The band/channel stacking module 520 may be substantiallysimilar to the band/channel stacking module 220 described with respectto FIG. 2, for example. Each of the LNA 502 ₁-502 _(N) may be operableto amplify, for example, weak satellite signals (e.g., RF₁—RF_(N)). Eachof the mixers 504 ₁-504 _(N) may be operable to downconvert a satellitefrequency band to, for example, an IF band or even to a basebandutilizing the LO₁-LO_(N) respectively. For example, one or more X, Kuand/or Ka satellite frequency bands may be downconverted to L-band. Thefilters 506 ₁-506 _(N) may be operable to filter signals outputted fromthe mixers 504 ₁-504 _(N), based on one or more criteria. For example,the filters 506 ₁-506 _(N) may be configured as low-pass filters(LPFs)—that is to pass low-frequency signals (below particularthreshold, or a “cutoff frequency”) and to attenuate signals withfrequencies higher than the “cutoff frequency”. The ADCs 508 ₁-508 _(N)may be operable to perform analog-to-digital conversions (e.g., onoutputs of the filters 506 ₁-506 _(N)). Each of the downconverteddigital signals 505 ₁-505 _(N) may be input to the frequency detectionmodule 530. Frequency information associated with each of the signals505 ₁-505 _(N) may then be analyzed by the frequency detection module530. The frequency detection module 530 may be operable to generate,based on the analyzing, information 510 which may be inputted to theband/channel stacking module 520. In this regard, the information 510may be substantially similar to the information 210 described withrespect to FIG. 2.

In an exemplary operation, the frequency detection module 530 mayperform functions as described with respect to the frequency detectionmodule 230 of FIG. 2, for example. In an exemplary embodiment of thedisclosure, the frequency detection module 530 may be operational indigital domain as the downconverted digital signals 505 ₁-505 _(N) arein the digital domain. In this regard, the frequency detection module530 may perform the analyzing using one or more of the following: a fastfourier transform (FFT), an edge detection and a center-of-masscomputation. An exemplary implementation for the FFT, the edge detectionand the center-of-mass computation is provided in FIG. 6. The frequencydetection module 530 may also be operable to determine, based on theedge detection, a symbol rate (or baud rate) associated with eachchannel for channel filtering in the band/channel stacking module 520,during at least the channel stacking operation, for example. In thisregard, the information 510, generated by the frequency detection module530, may also include information on the symbol rate (in addition to thefrequency offsets and the actual guard bands). For example, based on theedge detection, an actual lower edge and an actual higher edge of aparticular channel may be determined. Accordingly, a bandwidth of theparticular channel may be determined based on the lower edge and thehigher edge. In this regard, the symbol rate associated with theparticular channel may also be determined, as the symbol rate is afunction of the bandwidth.

In the example embodiment of the disclosure illustrated in FIG. 5,digitization (via the ADCs 508 ₁-508 _(N)) is shown to be implementedafter downconversion (via the mixers 504 ₁-504 _(N)). Notwithstanding,the disclosure may not be so limited. For example, downconversion (orfrequency translation) may be implemented after the digitization whichmay be implemented at the outputs of the low-noise amplifiers (LNAs 502₁-502 _(N)). In such instances, a “full spectrum capture” on inputsignals may be illustrated without departing from the spirit and scopeof various embodiments of the disclosure.

FIG. 6 is a block diagram illustrating an exemplary implementation offrequency analysis, in accordance with an example embodiment of theinvention. Referring to FIG. 6, there is shown a FFT 610, an edgedetection 620 and a center-of-mass computation 630. There is also showna channel signal 611 in frequency domain.

In the example implementation shown in FIG. 6, the FFT 610 may beapplied to a digital signal (such as the signal 505 ₁ of FIG. 5)corresponding to channels (or bands). The FFT 610 may convert, forexample, a channel signal from time-domain samples to frequency-domainsamples such as the channel signal 611. In this regard, the channelsignal 611 may be represented by a plurality of FFT bins 612. The edgedetection 620 may be used to determine a lower edge 621 and a higheredge 622, based on power level information associated with the FFT bins612. For example, based on a power level of a particular FFT binrelative to power levels of adjacent bins as well as based on acorresponding threshold 623, the edges 621, 622 may be determined by theedge detection 620. Accordingly, based on the edges 621, 622 and edgesof adjacent channels (or bands), one or more actual guard bands may bedetermined.

The center-of-mass computation 603 may be used to determine a centerfrequency 632 of the channel signal 611. The center-of-mass computation630 may compute or determine the center frequency 632, based on, forexample, power level information and frequency information associatedwith the FFT bins 612 and/or information on the edges 621, 622.Accordingly, based on the center frequency 632, a LO frequency offsetassociated with the channel signal 611 may be determined.

FIG. 7 is a flow chart illustrating exemplary steps for guard banddetection and frequency offset detection, in accordance with an exampleembodiment of the invention. Referring to FIG. 7, the exemplary stepsstart at step 701. In step 702, the signal processing circuit 120 may beoperable to analyze, using the frequency detection module 230, actualfrequency information 621, 622, 632 corresponding to a plurality ofdownconverted signals 205. Each of the plurality of downconvertedsignals 205 may be downconverted using one or more corresponding LOs(LO₁-LO_(N)) in the signal processing circuit 120. In step 703, by usingthe frequency detection module 230, the signal processing circuit 120may be operable to determine, for each of the downconverted signals 205and based on the analyzing, one or more of at least the following: (1)one or more frequency offsets 336, 346, which are associated with theone or more corresponding local LOs (LO₁-LO_(N)), in relation tocorresponding standard LO frequencies, and (2) one or more actual guardbands 334, 335, 344 between adjacent frequency bands. In step 704, thesignal processing circuit 120 may be operable to generate, using thefrequency detection module 230 and for the plurality of downconvertedsignals 205, information 210 on one or more of at least the following:the determined frequency offsets 336, 346 and the determined actualguard bands 334, 335, 344. In step 705, by using the frequency detectionmodule 230, the generated information 210 may be communicated to theband/channel stacking module 220 in the signal processing circuit 120.In step 706, the signal processing circuit 120 may then be operable toperform, based on the communicated generated information 210 and usingthe band/channel stacking module 220, one or both of a band stackingoperation and a channel stacking operation so that: (1) during the bandstacking operation, frequency bands 313, 323 are not stacked on eachother or stacked frequency bands 313, 323 do not overlap, and (2) duringthe channel stacking operation, channels 311, 312, 322 are not stackedon each other or stacked channels 311, 312, 322 do not overlap duringthe channel stacking operation. In step 707, the signal processingcircuit 120 may also be operable to perform, based on the communicatedgenerated information 210 and using the band/channel stacking module220, frequency corrections, in compliance with standard band frequenciesand standard channel frequencies, on output signals 350 of the bandstacking operation or output signals 350 of the channel stackingoperation, for channel tuning in a gateway such as the gateway 102. Theexemplary steps may proceed to the end step 708.

In various embodiments of the invention, a signal processing circuit120, which is operational within a satellite reception assembly 106, maybe operable to analyze actual frequency information 621, 622, 632corresponding to a plurality of downconverted signals 205. Each of theplurality of downconverted signals 205 may be downconverted using one ormore corresponding LOs (LO₁-LO_(N)) in the signal processing circuit 120(e.g., within LNBs 202 ₁-202 _(N)). For each of the downconvertedsignals 205 and based on the analyzing, one or more of at least thefollowing may be determined by the signal processing circuit 120: (1)one or more frequency offsets 336, 346, which are associated with theone or more corresponding LOs (LO₁-LO_(N)), in relation to correspondingstandard LO frequencies, and (2) one or more actual guard bands 334,335, 344 between adjacent frequency bands. The signal processing circuit120 may be operable to generate, for the plurality of downconvertedsignals 205, information 210 on one or more of at least the following:the determined frequency offsets 336, 346 and the determined actualguard bands 334. 335, 344. The generated information 210 may becommunicated to a band/channel stacking module 220 in the signalprocessing circuit 120.

The signal processing circuit 120 may then be operable to perform, basedon the communicated generated information 210 and using the band/channelstacking module 220, one or both of a band stacking operation and achannel stacking operation so that: (1) during the band stackingoperation, frequency bands 313, 323 are not stacked on each other orstacked frequency bands 313, 323 do not overlap, and (2) during thechannel stacking operation, channels 311, 312, 322 are not stacked oneach other or stacked channels 311, 312, 322 do not overlap during thechannel stacking operation. The signal processing circuit 120 may alsobe operable to perform, based on the communicated generated information210 and using the band/channel stacking module 220, frequencycorrections, in compliance with standard band frequencies and standardchannel frequencies, on output signals 350 of the band stackingoperation or output signals 350 of the channel stacking operation, forchannel tuning in a gateway 102. In this regard, the signal processingcircuit 120 may be operable to downconvert a plurality of RF signals(RF₁-RF_(N)) to the plurality of downconverted signals 205correspondingly, where each of the RF signals may correspond to one ormore satellite frequency bands, and the downconverted signals 205 maycomprises, for example, L-band signals or baseband signals. The signalprocessing circuit 120 may be operable to perform the analyzing, thedetermining, the generating and the communicating, using, for example, afrequency detection module 230 in the signal processing circuit 120.

In an exemplary embodiment of the disclosure, the frequency detectionmodule 430 may comprise a demodulator 440. In other instances, thefrequency detection module 430 may comprise, for example, at least aportion of a demodulator 440, where the at least a portion of thedemodulator may comprise a PLL 442.

In an exemplary embodiment of the disclosure, the plurality ofdownconverted signals 505 ₁-505 _(N) may be in digital domain and thefrequency detection module 530 may be operational in the digital domain.In such instances, the frequency detection module 530 may perform theanalyzing using one or more of the following: a FFT 610, an edgedetection 620 and a center-of-mass computation 630. The frequencydetection module 530 may also determine, based on the edge detection620, a symbol rate associated with each channel 611 for channelfiltering in the band/channel stacking module 520, during at least thechannel stacking operation, for example.

In an exemplary embodiment of the disclosure, each of the LOs(LO₁-LO_(N)) may comprise a dielectric resonant oscillator (DRO). Thegenerated information 210 may comprise, for example, a form of a matrix212, where each element of the matrix 212 may correspond to one of atleast the following: a particular frequency offset (e.g., the frequencyoffset 336) associated with a particular LO (e.g., the LO₁) and aparticular actual guard band (e.g., the guard band 334) associated witha particular downconverted signal (e.g., the signal 330).

Other embodiments of the invention may provide a non-transitory computerreadable medium and/or storage medium, and/or a non-transitory machinereadable medium and/or storage medium, having stored thereon, a machinecode and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for guard banddetection and frequency offset detection.

Accordingly, aspects of the present invention may be realized inhardware, software, or a combination of hardware and software. Thepresent invention may be realized in a centralized fashion in at leastone computer system or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

Aspects of the present invention may also be embedded in a computerprogram product, which comprises all the features enabling theimplementation of the methods described herein, and which when loaded ina computer system is able to carry out these methods. Computer programin the present context means any expression, in any language, code ornotation, of a set of instructions intended to cause a system having aninformation processing capability to perform a particular functioneither directly or after either or both of the following: a) conversionto another language, code or notation; b) reproduction in a differentmaterial form.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method, comprising: analyzing a plurality ofdownconverted signals, wherein said analyzing comprises performing acenter-of-mass computation; determining based on said analyzing of saidplurality of downconverted signals, for each of said plurality ofdownconverted signals, frequency related information associated with oneor more corresponding circuits used in obtaining said plurality ofdownconverted signals; performing, based on said frequency relatedinformation, one or both of a band stacking operation and a channelstacking operation; wherein: during said band stacking operation,frequency bands are not stacked on each other or stacked frequency bandsdo not overlap; and during said channel stacking operation, channels arenot stacked on each other or stacked channels do not overlap.
 2. Themethod of claim 1, comprising determining said frequency relatedinformation based on predefined frequency related parameters associatedwith said one or more corresponding circuits.
 3. The method of claim 1,wherein said frequency related information comprises frequency offsets.4. The method of claim 3, comprising determining said frequency offsetsbased on standard frequencies associated with said one or morecorresponding circuits.
 5. The method according to claim 1, comprisingperforming, based on said frequency related information, frequencycorrections, in compliance with standard band frequencies and standardchannel frequencies, on output signals of said band stacking operationor output signals of said channel stacking operation, for channel tuningin a gateway.
 6. The method according to claim 1, comprising generatingsaid plurality of downconverted signals based on a plurality of radiofrequency (RF) signals.
 7. The method according to claim 6, wherein eachof said RF signals corresponds to one or more satellite frequency bands,and said downconverted signals comprises L-band signals or basebandsignals.
 8. The method according to claim 1, wherein said analyzingfurther comprises performing one or both of: a fast Fourier transform(FFT) and an edge detection.
 9. The method according to claim 8,comprising determining based on said edge detection, a symbol rateassociated with each channel for channel filtering applied during atleast said channel stacking operation.
 10. The method according to claim1, comprising generating, based on said frequency related information, amatrix comprising one or more elements, with each of said one or moreelements of said matrix corresponding to a particular frequencyparameter associated with a particular one of said one or morecorresponding circuits.
 11. A system, comprising: a frequency detectioncircuit operable to: analyze a plurality of downconverted signals,wherein said analyzing comprises performing a center-of-masscomputation; and determine based on said analyzing of said plurality ofdownconverted signals, for each of said plurality of downconvertedsignals, frequency related information associated with one or morecorresponding circuits used in obtaining said plurality of downconvertedsignals; and a stacking circuit operable to perform, based on saidfrequency related information, one or both of a band stacking operationand a channel stacking operation, wherein: during said band stackingoperation, frequency bands are not stacked on each other or stackedfrequency bands do not overlap; and during said channel stackingoperation, channels are not stacked on each other or stacked channels donot overlap.
 12. The system according to claim 11, wherein saidfrequency detection circuit is operable to determine said frequencyrelated information based on predefined frequency related parametersassociated with said one or more corresponding circuits.
 13. The systemaccording to claim 11, wherein: said frequency related informationcomprises frequency offsets; and said frequency detection circuit isoperable to determine said frequency offsets based on standardfrequencies associated with said one or more corresponding circuits. 14.The system according to claim 11, wherein said stacking circuit isoperable to perform, based on said frequency related information,frequency corrections, in compliance with standard band frequencies andstandard channel frequencies, on output signals of said band stackingoperation or output signals of said channel stacking operation, forchannel tuning in a gateway.
 15. The system according to claim 11,comprising one or more signal processing circuit operable to generatesaid plurality of downconverted signals based on a plurality of radiofrequency (RF) signals.
 16. The system according to claim 11, whereinsaid frequency detection circuit is operable to, when performing saidanalyzing of said plurality of downconverted signals, further performone or both of: a fast Fourier transform (FFT) and an edge detection.17. The system according to claim 16, wherein said frequency detectioncircuit is operable to determine based on said edge detection, a symbolrate associated with each channel for channel filtering applied duringat least said channel stacking operation.
 18. The system according toclaim 11, wherein said frequency detection circuit is operable togenerate based on said frequency related information, a matrixcomprising one or more elements, with each of said one or more elementsof said matrix corresponding to a particular frequency parameterassociated with a particular one of said one or more correspondingcircuits.
 19. The system according to claim 11, wherein said frequencydetection circuit comprises a demodulator.
 20. The system according toclaim 11, wherein said frequency detection module comprises a phaselocked loop (PLL).
 21. The system according to claim 11, wherein saidone or more corresponding circuits comprise one or more localoscillators (LOs).
 22. The system according to claim 21, wherein each ofsaid one or more local oscillators (LOs) comprises a dielectric resonantoscillator (DRO).